NASA is eyeing three geologically intriguing places on Mars—Jezero crater, Northeast Syrtis, and Columbia Hills—as possible landing sites for its next rover, to be launched in 2020. The agency announced the finalists last week follow- ing a 3-day meeting of nearly 200 scientists inMonrovia, California. Jezero, once home to an ancientriver delta that may have collected and preserved or-ganic molecules, was the clear favorite among scientistsduring an advisory vote that preceded the decision. Insecond place was nearby Syrtis, a carbonate-rich localehome to water-associated clays that could have onceharbored life deep in the planet’s interior. But the choiceof Columbia Hills, previously explored by the Spiritrover, came as a surprise: The site’s silica deposits couldbe evidence of a past hydrothermal spring, but thatinterpretation is uncertain. NASA wanted to leave opena potential third system, says John Grant, a planetaryscientist at the Washington, D.C.–based SmithsonianInstitution, who led the meeting. The burden of proofon Columbia Hill advocates, he added, “is high.” The

$2 billion Mars 2020 rover’s ultimate goal is to drill
some 30 rock cores; they’ll be cached on the planet’s
surface for return to Earth during a subsequent mission.

Mars scientists close in on sites for 2020 landing

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13 February, demanding that it restore pub-lic access to tens of thousands of documentsscrubbed from the department’s websiteon 3 February. The information includesinspection reports from more than 7800

The plaintiffs are People for the Ethical
Treatment of Animals, four other animal
welfare groups, and Delcianna Winders, an
academic fellow with the Harvard Animal
Law & Policy Program. They allege that
USDA violated the Freedom of Information
Act in removing the data. Also on Monday,

19 Democratic U.S. senators wrote to the

“I am not sufficiently conceited to think that my sun is the only one with a family of planets.” Winston Churchill in his 1939 article “Are We Alone in the Universe?” recently found at the U.S. National Churchill Museum in Fulton, Missouri, and described in Nature.

A deltalike fan marks where
water would have flowed
into Jezero crater, possibly
transporting organic molecules.